What was I thinking? If version 8.2 free was a major resource hog, of course 9.0 Pro will be, and then some! I've exited the program through the tray icon, and what a difference. Like I've got my system back. My curiosity is satisfied, and I will no doubt be uninstalling Ad-Aware soon. BTW, I have plenty of disk space, 3.0GB of memory, a 3.0GHz processor, XP Pro SP3, so I don't think resources are an issue here.
Copmom, in this case I agree. Like I said, I don't think you're missing much. I haven't been using Ad-Aware much recently. And Comodo Internet Security Suite (the free version) is doing a pretty good job for me. I do think I'll install a couple of the privacy options mentioned by Graylox recently, like Abine and the Firefox addon Better Privacy. One at a time, and see how it goes.
I still use Spybot S&D, and may try Malwarebytes, as Tailteann mentioned. Thanks, all.
